wilc1000: added queue support for WMM

Added multiple queues[BK,BE,VI,VO] to handle different priority data
packets. Before adding a packet to the queue, checked its priority from
the header, and then add to the suitable queue. The limit for each queue
is maintained separately. Also while passing the packets to the firmware
via VMM take care to select data packets based on priority and available
space.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201125114059.10006-6-ajay.kathat@microchip.com